Planimeter.



W. I. DURAND.

rLAnmnm.

APPLIOATIOI FILED APR. 7. 1909.

Patented July 6, 1909.

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planimeters; and an object of my invention is.

WILLIAM F. DURANI), OF STANFORD UNIVERSITY, CALIFORNIA.

PLANIMETER.

Specification of Letters Patent.

Application filed April 7, 1909. Serial No. 488.374.

Patented July 6, 1909.

To all whom it may concern: I

Be it known that 1, WILLIAM F. DURAND, a citizen of the United States, residing at Stanford University, in the county of Santa Clara and State of California, have invented l certain new and useful Improvements "Planimeters, of which the following is a speci fication, reference being had to the accoml p anying drawings.

My invention relates to improvements in to provide a lanimeter adapted for use in determining the mean radial ordinate of diagrams plotted in polar coordinates. Dialrecording gage instruments which trace a diagram in polar coordinates but the tracing arm of which follows a curvilinear path have gone into general use for recording various engineering uantities, mechanical, thermal and electrica. It has become desirable to ascertain the mean radial ordinate of such (if agrams; and it is an object of my invention to provide an integrating or averaging l11 strument by means of which this desired quantity may be obtained. My new instrument is adapted, of course, to be used in con nection with diagrams plotted by the mark ing point moving in and out on straight radial lines (such as diagrams of crank-turning effort) as well as in connection with diagrams in which the marking point moves in arcs of circles.

In the drawings illustrating the principle of my invention and the best mode now known to me of applying that principle, Fig ure 1 is a plan view of mv new plauimetcr; Fig. 2 is a central, longitudinal. section on the line A- A of Fig. 1 Fig. 3 is a section on the line B-B of Fig. l Fig. 4; is an end view looking in the direction of the arrow of Fig. 1; Fig. 5 is a plan of a modifiedv form; and Fig. 6 is an elevation of the planimeter shown in plan in Fig.

Upon the base-platc at is mounted free to turn the two-part gricle-plate c which consists of the bottomilate d and the top-plate e fastened together y the screws 7 and each formcdwith a pair of grooves g lined with cloth it. Through the grooves g passes a pair of carrier-rods or guide-bars i which support at one end the tracer-carrying frame j n 'whigh is rigidly mounted the tracer 7r. On eaclrside of the latter is a log or post I). Mounted upon the pivot-screws m free to swing in the tracer-carrying frame is the wheel-frame n in which is mounted free to rotate the wheelshaft o. The outer end of the latter is so ported. by the ivot-screW m. Upon the w 1eel-shaft 0 is rigidly fastened the integrating wheel 10 and to the inner end of the wheel-frame n and adjacent to the integrating-wheel p is fastened the Vernier-plate 51. Upon the wheel-shaft 0 is formed a worm r which meshes with a worm-wheel s at the lower end of a vertical shaft t-which is journaled in the bracket it carried by the wheelframe a. Upon the upper end of the shaft 15 is a counter-wheel w which indicates the number of revolutions made by the integrating-wheel p. Itwill be understood that the carrier-bars i arefrec to slide lengthwise in the cloth-lined grooves 9 without lost motion; and (shat the shaft 0, which carries the integratrt wheelp, lies in the same vertical plane wit. t e pivot-post 90' upon which the guide late c turns and which is rigidly connecte with the bottom late d.

In the modified form s own in Figs. 5 and 6, the rear end of the carrier-bar i is joined by the connecting plate y to a pair of guidebars i which pass through grooves in a base block a. Upon the latter is mounted free to rotate a diagram-plate z. The tracer 7c is carried at the outer end of the tracer-frame j. The wheel-frame n and the parts carried by it are substantially the same members illustrated. in Figs. 1 and 2. The lower face of each of the base-blocks a, a are formed with pin points a by which. they engage in the surface upon which the instrument is supported.

In Figs. 1 and2 the diagram-support is the table or board 2 upon which the instrument is mounted for the time being.

I claim:

1.. A planimeter consisting of the combination of a base; a guiding device mounted free to rotate on said base; a guide bar mounted free to slide lengthwise in said guiding device; a. tracer carried by said guidebar; and an integrating wheel carried by said guide-bar.

2. A planimetcr consisting of the combination of a base; a guiding device mounted free to rotate on said base; a guide-bar mounted free to slide lengthwise in said guiding device; a tracer carried by said. guidebar; a wheel-frame mounted free to swing in said guide-bar; and an integrating wheel carried by said wheel-frame.

3. In a plenimeter, the combination of a relatively end the friction between them stationary base;' a guide bar supported I serving to drive said wheel. thereby free to slide lengthwise; a tracer; In testimony whereof I haveheieunto set and an integratin wheel, said tracer and my hand at said Stanford University, this 15 5 Wheel being cerrie .by-said guide-hm; 30th day of March A. D. 1909, in the pres- 4(.1 I? COIllbiIlfltiOl, it stfiziorfmry basefda ence of the two-undersigned witnesses. 'ui e- :11 su orte tiere me to si e 1 l engthwis e; amtraeer; an intiz grating wheel, DURAND' the latte'i 'fiand said wheel being carried by Witnesses: 10 said uideeber; and adiagram-support, said F. A. STEVENS,

whee and" diagram-support being movable 1 E. CORBALEY. 

